Light is a sine wave

[Benjamin Smith]

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A random insight that popped into my head: a Pockels cell or half-wave
plate is effectively running an autocorrelation function on the laser light
when combined with a glan-laser polarizer.  The resulting intensity vs.
voltage of a Pockels cell or intensity vs. angle of a half wave plate
follows a sine wave, which proves that the light wave itself is also a sine
wave.  Little did I know I've been directly measuring the geometry of light
waves all these years.

The fact that light is a sine wave is one of those things you simply take
for granted, until you start to think about it a little more.

-Ben Smith

--
Benjamin E. Smith, Ph. D.
Imaging Specialist, Vision Science
University of California, Berkeley
195 Weill Hall
Berkeley, CA  94720-3200
Tel  [phone]
Fax [phone]
e-mail: [hidden email]
https://vision.berkeley.edu/faculty/core-grants-nei/core-grant-microscopic-imaging/

[Craig Brideau]

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I always envisioned it as a series of sheets of paper traveling in the
direction normal to the faces of the sheets. Each piece of paper represents
a maxima, and the point directly between two sheets is the minima. With
some mental squinting you can replace the sheets with gradients of
electromagnetic fields to perceive the sine wave. The paper analogy is also
useful for explaining spatial chirp, where the sheets of paper are tilted
with respect to their direction of travel and are no longer traveling
normal to the plane.

Craig

On Tue, May 25, 2021 at 10:37 AM Benjamin Smith <[hidden email]>
wrote:

> *****
> To join, leave or search the confocal microscopy listserv, go to:
> http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
> Post images on http://www.imgur.com and include the link in your posting.
> *****
>
> A random insight that popped into my head: a Pockels cell or half-wave
> plate is effectively running an autocorrelation function on the laser light
> when combined with a glan-laser polarizer.  The resulting intensity vs.
> voltage of a Pockels cell or intensity vs. angle of a half wave plate
> follows a sine wave, which proves that the light wave itself is also a sine
> wave.  Little did I know I've been directly measuring the geometry of light
> waves all these years.
>
> The fact that light is a sine wave is one of those things you simply take
> for granted, until you start to think about it a little more.
>
> -Ben Smith
>
> --
> Benjamin E. Smith, Ph. D.
> Imaging Specialist, Vision Science
> University of California, Berkeley
> 195 Weill Hall
> Berkeley, CA  94720-3200
> Tel  [phone]
> Fax [phone]
> e-mail: [hidden email]
>
> https://vision.berkeley.edu/faculty/core-grants-nei/core-grant-microscopic-imaging/
>

[Benjamin Smith]

*****
To join, leave or search the confocal microscopy listserv, go to:
http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
Post images on http://www.imgur.com and include the link in your posting.
*****

Along those same lines as the spatial chirp, I also find it easier to use
the paper/blob analogy to visualize shearing in Nomarski prisms and to
visualize  the effect of phase plates used in STED, or anything involving
orbital angular momentum for that matter.

Speaking of light as paper sheets, it also blew my mind when I did out the
math and realized that a 140 fs laser pulse is a thin sheet of light with
the thickness of a piece of lens paper, and at 80 MHz those pieces of lens
paper are separated by the width of a small room.  It really helped to
drive home how insanely powerful each pulse is.  Then factor in that all
that power (over 100 kW per pulse) is squeezed to a 10 femtoliter volume at
the sample plane, and you begin to really appreciate how ridiculous 2P
microscopy really is.

On Tue, May 25, 2021 at 9:48 AM Craig Brideau <[hidden email]>
wrote:

> *****
> To join, leave or search the confocal microscopy listserv, go to:
> http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
> Post images on http://www.imgur.com and include the link in your posting.
> *****
>
> I always envisioned it as a series of sheets of paper traveling in the
> direction normal to the faces of the sheets. Each piece of paper represents
> a maxima, and the point directly between two sheets is the minima. With
> some mental squinting you can replace the sheets with gradients of
> electromagnetic fields to perceive the sine wave. The paper analogy is also
> useful for explaining spatial chirp, where the sheets of paper are tilted
> with respect to their direction of travel and are no longer traveling
> normal to the plane.
>
> Craig
>
> On Tue, May 25, 2021 at 10:37 AM Benjamin Smith <
> [hidden email]>
> wrote:
>
> > *****
> > To join, leave or search the confocal microscopy listserv, go to:
> > http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
> > Post images on http://www.imgur.com and include the link in your
> posting.
> > *****
> >
> > A random insight that popped into my head: a Pockels cell or half-wave
> > plate is effectively running an autocorrelation function on the laser
> light
> > when combined with a glan-laser polarizer.  The resulting intensity vs.
> > voltage of a Pockels cell or intensity vs. angle of a half wave plate
> > follows a sine wave, which proves that the light wave itself is also a
> sine
> > wave.  Little did I know I've been directly measuring the geometry of
> light
> > waves all these years.
> >
> > The fact that light is a sine wave is one of those things you simply take
> > for granted, until you start to think about it a little more.
> >
> > -Ben Smith
> >
> > --
> > Benjamin E. Smith, Ph. D.
> > Imaging Specialist, Vision Science
> > University of California, Berkeley
> > 195 Weill Hall
> > Berkeley, CA  94720-3200
> > Tel  [phone]
> > Fax [phone]
> > e-mail: [hidden email]
> >
> >
> https://vision.berkeley.edu/faculty/core-grants-nei/core-grant-microscopic-imaging/
> >
>

--
Benjamin E. Smith, Ph. D.
Imaging Specialist, Vision Science
University of California, Berkeley
195 Weill Hall
Berkeley, CA  94720-3200
Tel  [phone]
Fax [phone]
e-mail: [hidden email]
https://vision.berkeley.edu/faculty/core-grants-nei/core-grant-microscopic-imaging/